1. Field of the Invention
The present invention relates to a connection structure for an electric wire and a terminal, a connection method therefor and a terminal connecting apparatus, and more particularly, to a connection structure for an electric wire and a terminal, a connection method therefor and a terminal connecting apparatus capable of strongly connecting the electric wire and the terminal irrespective of plate thickness and strength of the terminal and capable of reducing variation of crimp at the time of swaging.
2. Description of the Related Art
As one method for connecting a terminal to an electric wire, a method disclosed in Japanese Patent Application Laid-open No. S61-253774 is proposed. According to this method, as shown in FIGS. 1A and 1B, an electric wire cover crimping portion 102 of a terminal 101 is formed with an incision 103 of substantially U-shape as viewed from top. Portions of the terminal 101 facing the incision 103 are bent inward to form biting pieces 104 and 104. The biting pieces 104 and 104 are allowed to bite into an insulative outer skin 105 of the electric wire as shown in FIG. 1C so as to swag the electric wire cover crimping portion 102 together with the insulative outer skin 105.
Since the electric wire cover crimping portion 102 is swaged with the insulative outer skin 105 of the electric wire and at the same time, the biting pieces 104 and 104 bite into the insulative outer skin 105 in this manner, the terminal 101 can be connected to the electric wire with one swaging operation. Further, since the biting pieces 104 and 104 bite into the insulative outer skin 105, connecting and holding force of the terminal 101 and the electric wire is enhanced.
However, the biting pieces 104 and 104 need to have strength enough to withstand pressure when swaging the electric wire cover crimping portion 102 and it is necessary to increase thickness of the pieces 104 and 104. Further, since the biting pieces 104 and 104 are formed by bending using a mold, it is troublesome to form the pieces as compared with a terminal having no biting pieces 104 and 104, and cost of the mold is also high. The terminal 101 may be deviated right/left and forward/backward with respect to the electric wire in some cases, and this causes variation at the time of swaging.
Thereupon, the present invention has been achieved to solve the above problems, and it is an object of the invention to provide a connection structure for an electric wire and a terminal, a connection method therefor and a terminal connecting apparatus capable of strongly connecting the terminal to the electric wire by allowing the terminal to uniformly bite into an insulative outer skin of the electric wire irrespective of relation of thickness and strength of the terminal, and capable of preventing positional deviation between the terminal and the electric wire at the time of swaging.
To achieve the above object, a first aspect of the present invention provides connecting structure for an electric wire and a terminal, comprising an insulative outer skin provided on the electric wire, an electric wire cover crimping portion provided on the terminal, and a hole formed in the electric wire cover crimping portion, wherein when the terminal is connected to the electric wire, the insulative outer skin is mounted to the electric wire cover crimping portion, the electric wire cover crimping portion is swaged and at the same time, an opening peripheral edge a of the hole is allowed to bite into the insulative outer skin.
Since the opening peripheral edge a of the hole formed in the electric wire cover crimping portion of the terminal is allowed to bites into the insulative outer skin of the electric wire in this manner, the biting piece of the opening peripheral edge a becomes an edge, and the holding force between the terminal and the electric wire is further enhanced.
A second aspect of the present invention provides a connecting method for an electric wire and a terminal, wherein an electric wire cover crimping portion of the terminal is formed with a hole and then, an insulative outer skin of the electric wire is mounted to the electric wire cover crimping portion, the electric wire cover crimping portion is swaged and at the same time, a projection is allowed to face the hole to project the projection upward toward the insulative outer skin, thereby allowing an opening peripheral edge a of the hole to bite into the insulative outer skin.
If the projection facing the hole formed in the electric wire cover crimping portion is pushed upward toward the insulative outer skin, the opening peripheral edge a of the hole is pushed upward toward the insulative outer skin, and the pushed up portion thereof becomes a biting piece, thereby securing the terminal and the electric wire to each other. Since a tip end the biting piece at that time becomes the edge, the opening peripheral edge a bites into the insulative outer skin strongly, and the holding force of the terminal and the electric wire is further enhanced.
Further, the electric wire cover crimping portion is swaged and at the same time, the opening peripheral edge a of the hole is pushed up by the projection. Therefore, it is possible to allow the biting piece of the opening peripheral edge a to bite uniformly irrespective of thickness and strength of the terminal. Further, the projection faces the hole and thus, positioning between the terminal and the electric wire is carried out when the electric wire cover crimping portion is swaged. When the electric wire cover crimping portion is swaged, positional deviation of the terminal and the electric wire right/left and forward/backward is restricted and variation by crimping is also restrained.
The terminal is only required to have the hole, it is unnecessary to form the terminal into a complicated shape unlike the conventional terminal, the number of manufacturing steps of the terminal can be reduced, and the costs can also be lowered.
A third aspect of the present invention provides a terminal connecting apparatus comprising a terminal mount for mounting the terminal having an electric wire cover crimping portion formed with a hole in a state in which the hole faces a projection, and a swaging member for swaging the electric wire cover crimping portion of the terminal mounted to the terminal mount into an insulative outer skin of the electric wire, wherein the electric wire cover crimping portion is swaged with the insulative outer skin by the swaging member and at the same time, an opening peripheral edge a of the hole is allowed to bite into the insulative outer skin.
In this apparatus of the invention, since the projection facing the hole formed in the terminal is formed on the terminal mount, the projection faces the hole and the terminal is positioned with respect to the terminal mount, and positional deviation between the terminal and the electric wire is prevented when the electric wire cover crimping portion is swaged.